function [ status ] = mx_eyelink_open( )
%MX_EYELINK_OPEN Attempts to open a link connection to the EyeLink tracker.
% Simple connect to single Eyelink tracker. Equivalent to
% eyelink_open_node(broadcast_address, 0).
%
% Remarks: 
% The tracker address can be set by calling the function 
% set_eyelink_address(). If this address was "255.255.255.255" the call to 
% eyelink_open() will "broadcast" a request to any tracker, however this may
% fail if multiple Ethernet cards are installed. For the broadcast option to
% work use EyeLink I v2.1 or higher, EyeLink II v1.1 or higher. Before using
% this command, call either open_eyelink_connection(-1) or 
% open_eyelink_system () to prepare the link for use.
%
% Returns:
% 0 if successful.
% -200 if link could not be established.
% -201 if tracker did not respond.
% -203 if the versions of the EyeLink library and tracker are incompatible.
%
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% Copyright Eduardo Aponte 2013
% aponteeduardo@gmail.com